From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CAA5C433E6 for ; Thu, 21 Jan 2021 08:53:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D436723A53 for ; Thu, 21 Jan 2021 08:53:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728253AbhAUIxY (ORCPT ); Thu, 21 Jan 2021 03:53:24 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:46312 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728162AbhAUIwo (ORCPT ); Thu, 21 Jan 2021 03:52:44 -0500 Received: from mail-ej1-f71.google.com ([209.85.218.71]) by youngberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1l2VhB-0000aV-Pe for linux-kernel@vger.kernel.org; Thu, 21 Jan 2021 08:52:01 +0000 Received: by mail-ej1-f71.google.com with SMTP id v11so480146ejx.22 for ; Thu, 21 Jan 2021 00:52:01 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=GS6uyl18DS5/tavzuQl/Q5aTYUmkCKLCcwIE6hhMVf8=; b=q2dSSqLnbOMeUJOIaQYya2F7gIcOzD25mvTHPLnO3zNrdvWFLxszWXeryJOmSJU0Gc 42Oi7xEskjZXQqNlcklEjYEpfg2fiWiHIJXs8b/8U5rJa7R5l8vupiWmgPgba63lVADZ bJGobtkSJI8xDZuj13mBOFqXK90inrLvNLmU/myz9KRBxn4KDctfzC8TmspYwIajuybW eYQUGcBOVUAd05itKtU7mjVE8bBkCa58bH9WYeZ42FQ9HKMOgBnGoEjdsIF1B4uNQqdu xOHxMLn7QVi5vv4GDio5Bj64W9xwy6EGXEYrpkNlnMF/V3FImdA7dvfXB6LC3/nH00uU dnnQ== X-Gm-Message-State: AOAM5310/oqD0ftjZ9ESVzc/RXNrBJ3iobndZzoWTP8tj2Tgonr9le8L nlY8uL902sHWKUaoRd+zGkwSdbmwDf+sEvveUBirib7awOjdbRqLIA0D+WQR7+1j8p3cNuFeVCK G6+0v0Q7u1PnTOratg9kXY6KKYEV96lXveeKb1HA13Q== X-Received: by 2002:a17:906:3b97:: with SMTP id u23mr8458743ejf.147.1611219121170; Thu, 21 Jan 2021 00:52:01 -0800 (PST) X-Google-Smtp-Source: ABdhPJzvJfiKbOKkjZDF6lmyAN2L3bi0sbtRcMnGkDUWOTFgdjS6xZ6S9hdOVwWiufnA1Evdn8LRMA== X-Received: by 2002:a17:906:3b97:: with SMTP id u23mr8458724ejf.147.1611219120941; Thu, 21 Jan 2021 00:52:00 -0800 (PST) Received: from localhost (host-79-52-126-228.retail.telecomitalia.it. [79.52.126.228]) by smtp.gmail.com with ESMTPSA id ce7sm1937436ejb.100.2021.01.21.00.52.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Jan 2021 00:52:00 -0800 (PST) Date: Thu, 21 Jan 2021 09:51:59 +0100 From: Andrea Righi To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, Borislav Petkov , x86@kernel.org Subject: Re: [tip: x86/entry] x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y Message-ID: References: <161121327995.414.14890124942899525500.tip-bot2@tip-bot2> <20210121074928.GA1346795@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210121074928.GA1346795@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 21, 2021 at 08:49:28AM +0100, Ingo Molnar wrote: > > * tip-bot2 for Andrea Righi wrote: > > > The following commit has been merged into the x86/entry branch of tip: > > > > Commit-ID: e6d92b6680371ae1aeeb6c5eb2387fdc5d9a2c89 > > Gitweb: https://git.kernel.org/tip/e6d92b6680371ae1aeeb6c5eb2387fdc5d9a2c89 > > Author: Andrea Righi > > AuthorDate: Thu, 14 Jan 2021 12:48:35 +01:00 > > Committer: Ingo Molnar > > CommitterDate: Thu, 21 Jan 2021 08:11:52 +01:00 > > > > x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y > > > > With CONFIG_PREEMPTION disabled, arch/x86/entry/thunk_64.o is just an > > empty object file. > > > > With the newer binutils (tested with 2.35.90.20210113-1ubuntu1) the GNU > > assembler doesn't generate a symbol table for empty object files and > > objtool fails with the following error when a valid symbol table cannot > > be found: > > > > arch/x86/entry/thunk_64.o: warning: objtool: missing symbol table > > > > To prevent this from happening, build thunk_$(BITS).o only if > > CONFIG_PREEMPTION is enabled. > > > > BugLink: https://bugs.launchpad.net/bugs/1911359 > > > > Fixes: 320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft") > > Signed-off-by: Andrea Righi > > Signed-off-by: Ingo Molnar > > Cc: Borislav Petkov > > Link: https://lore.kernel.org/r/YAAvk0UQelq0Ae7+@xps-13-7390 > > Hm, this fails to build on UML defconfig: > > /home/mingo/gcc/cross/lib/gcc/x86_64-linux/9.3.1/../../../../x86_64-linux/bin/ld: arch/x86/um/../entry/thunk_64.o: in function `preempt_schedule_thunk': > /home/mingo/tip.cross/arch/x86/um/../entry/thunk_64.S:34: undefined reference to `preempt_schedule' > /home/mingo/gcc/cross/lib/gcc/x86_64-linux/9.3.1/../../../../x86_64-linux/bin/ld: arch/x86/um/../entry/thunk_64.o: in function `preempt_schedule_notrace_thunk': > /home/mingo/tip.cross/arch/x86/um/../entry/thunk_64.S:35: undefined reference to `preempt_schedule_notrace' > > Thanks, > > Ingo I've been able to reproduce it, I'm looking at this right now. Thanks! -Andrea